N-bromobutanimide → Tert-butyl 2-{2-[6-bromo-3-(2,2-dimethylpropionylamino)-2-methoxycarbonylphenyl]-ethyl}-pyrrolidine-1-carboxylate

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Reaction Steps

N-Bromosuccinimide (1.24 g) was added to a solution of tert butyl 2-{2-[3-(2,2-dimethyl-propionylamino)-2-methoxycarbonylphenyl]-ethyl}-pyrrolidine-1-carboxylate (Intermediate 37, 2.74 g) in acetonitrile (40 mL) and the resultant mixture was stirred for 1 hour at room temperature. The mixture was concentrated in vacuo and the residue was partitioned between ethyl acetate and water. The organic layer was dried (Na2SO4) and filtered and the filtrate was concentrated in vacuo. The residue was purified by chromatography on silica, eluting with a mixture of ethyl acetate and cyclohexane with a gradient of 0-25% to give tert butyl 2-{2-[6-bromo-3-(2,2-dimethylpropionylamino)-2-methoxycarbonylphenyl]-ethyl}-pyrrolidine-1-carboxylate (2.55 g) as a colourless gum.

Provenance & Evidence